This painting is from back-in-the-day when I used to paint from B&W photos, so all the colors are imagined.

Back then I shot B&W and then developed the film and made the prints.

I would project the print onto an 11x14 sheet of paper and then trace the lines in pencil as well as possible in the dim light.

I would "carbon" the back of the tracing, and transfer it to the watercolor paper.